Drying oils



United States Patent D DRYWG OILS August R. Hempel and Paul E. Marling,Dayton, Ohio, assignors to Monsanto Chemical Compuy, St. Louis, Mo., acorporation of Delaware No Drawing. Application September 24, 1952,Serial No. 311,332

Claims. (Cl. 269404.8)

The present invention relates to drying oils and more particularlyprovides new and improved rapidly drying oils and methods of producingthe same.

According to the invention, the drying rate of fatty oils is acceleratedby first condensing them with a certain proportion of fumaric acid,whereby there are formed fatty oil-furnaric acid adducts containing freecarboxy radicals, and then esterifying said adducts withpentaerythritol. Fatty oils suitably used for the preparation of thepresent improved drying oils are non-conjugated, unsaturated,non-hydroxylated fatty oils having from 10 to 24 carbon atoms in thecarbon chain of the fatty acids of the oils. As examples of useful oilsmay be mentioned soybean, linseed, olive, perilla, safilower, codliver,whale, sardine, rape seed, sunflower, corn, grape seed and cotton seedoils. The fatty oils may be of a nondrying, semi-drying or drying type.

It is old in the art to condense such oils with acyclic olefinicdicarboxylic acids or anhydrides thereof, usually maleic anhydride, toform addition products which may be esterified to give viscous to solidresinous materials, c. g., as described broadly in the Clocker PatentsNos. 2,188,882890 and 2,275,843. Now we have found that when the fattyoils are reacted with from 3 per cent to less than 10 per cent by weightof fumaric acid, based on the weight of the oil, and the resultingaddition products are esterified with pentaerythritol, there areobtained oily reaction products possessing improved dryingcharacteristics. Oils of poor drying properties are particularlymodified. Thus, by the present treatment, soybean oil or safflower oil,which are oils of the semidrying type, are converted into oils having adrying rate which far exceeds that of some drying oils, e. g., bodiedlinseed oil, and is substantially equal to that of the similarly treatedlinseed oil, i. e., the pentaerythritol ester of linseed oil-fumaricacid adduct. We have found, for example, that whether one starts withlinseed oil or safliower oil, reaction of the oil with fumaric acid inthe proportions shown above, and subsequent esterification of theoil-fumaric acid adduct gives in each case an oil which dries tack-freein six hours. This is unexpected from prior art knowledge of esterifiedfatty-oil-maleic anhydride adducts, wherein the drying rates of productsprepared from drying oils were generally more rapid than the dryingrates of products obtained from thesemi-drying oils. We have also foundthat the use of fumaric acid, specifically, as the dicarboxylicadduct-forming component and pentaerythritol, specifically, as theesterifying alcohol is critical in obtaining the significant improvementin drying rate attained by the present invention. Contrary to resultsproduced with maleic anhydride, reaction of the fatty oil with fuman'cacid results in little, if any change in drying properties of the oil.Thus, the fumaric acid adducts of soybean, linseed, cotton seed orsafliower oil all have drying times which are greater than 48 hours;whereas, as is known in the art, reaction of the same oils with maleicanhydride results 2,754,307 Patented July 10, 1955 ICC.

in products of considerably improved drying properties. In order toobtain a significant change in drying time when employing fumaric acidinstead of maleic anhydride, there must be employed only from 3 per centto less than 10 per cent of furnaric acid in preparing the adducts, andthe resulting adducts must be further reacted with an esterifying agent.Here again, however, the effect of the esterifying agent on drying timeimprovement is unexpectedly critical. The glycerine ester of soybeanoil-furnaric acid adduct has substantially the drying rate possessed bythe glycerine ester of soybean oil-maleic anhydride adduct; thepentaerythritol ester of soybean oil-fumaric acid adduct has a dryingrate which is much more rapid than that of the pentaerythritol ester ofsoybean oil-maleic anhydride adduct, although the soybean oil-maleicanhydride adduct, before esterification, has a drying rate which isconsiderably higher than the drying rate of the soybean oil-fumaric acidadduct before esterification.

The present invention provides a new and very etiicient method forimproving the drying rates of non-conjugated, unsaturated,non-hydroxylated fatty oils, generally. It further provides for thecoating industries a new paint and varnish vehicle of superior dryingproperties and great economic value. The present invention also servesthe agricultural industry in providing for it transformation of suchreadily available, but poorly drying, oils, as soybean oil, saffloweroil and cotton seed oil into highly desirable technical commodities.

In improving the drying rates of the fatty oils, it is preferred tooperate substantially as follows:

A mixture consisting of the fatty oil and from 3.0 per cent to less than10 per cent by weight of fumaric acid is processed with agitation and inan inert atmosphere at a temperature of from 300 F. to 500 F. untilcompletion of the addition reaction. Depending upon the reactionconditions used, i. e., the quantities involved, agitation, andtemperature, the processing time may Vary from a period of severalminutes to several hours. Progress of the addition reaction may befollowed by noting the acid value of the reaction mixture at intervals.To the clear reaction mixture so obtained, which reaction mixturecomprises the fatty oil-fumaric acid adduct, there is then addedpentaerythritol in an amount calculated to esterify the free carboxygroups of the adduct. The mixture of adduct and pentaerythritol is thenheated until esterification has been substantially completed. This maybe gauged either by noting the quantity of water involved or bydetermining the Viscosity and/or acid value changes in samples taken atintervals from the reaction mixture. Temperatures employed in theesterification reaction are generally of the same order used for thepreparation of the adduct.

In preparing the present rapid drying oils, it is imperative that theproportion of fumaric acid to fatty oil be adhered to within the limitsdefined above. The use of amounts of fumaric acid which are less than 3per cent by weight of the fatty oil does not result in substantialmodification of the drying rate of the oil and the use of 10 per cent ormore of the fumaric acid based on the weight of the fatty oil is notdesirable in that products of poor viscosity, and even of a gel-like tosolid, resinous nature, may be thereby obtained. When employing at least3 per cent but less than 10 per cent of the fumaric acid, however, andreacting the resulting adducts with pentaerythritol to substantiallycomplete esterification, there are obtained highly viscous, clear,yellow to colorless oils having low acid values, very good thermalstability and excellent drying properties. The present drying oils arethus of outstanding usefulness in the formulation of rapid-dryingpaints, varnishes and enamels.

The invention is further illustrated but not limited by the followingexamples:

Example 1 Two-hundred g. of soybean oil was charged to athreenecked 500cc. flask which was provided with a constant feed of carbon dioxide. Theoil was heated to a temperature of 250 F. and 10 g. of fumaric acid byweight of the oil) was added to it. The resulting mixture was thenheated, with mechanical agitation and in a carbon dioxide atmosphere,for about 1.2 hours at a temperature of 500 F. A sample taken from thereaction mixture at this point had an acid value of 21.6. Externalheating was then discontinued and to the reaction mixture there wasadded 6.46 g. of technical pentaerythritol, and heating of'the whole wasresumed at a temperature of 525 F. for 1.5 hours. At the end of thattime determination of the acid value of the reaction mixture showedsubstantially complete esterification. The esterified adduct had a colorof 6 (Gardner), and viscosity L-N (Gardner-*Holdt), and an acid value of9.8.

Example 2 Example 3 A mixture consisting of 300 g. of soybean oil and17.0 g. of fumaric acid was processed, in a carbon dioxide atmosphere ata temperature of 520 F. A sample taken from the reaction mixture at theend of 45 minutes of heating had an acid value of 32.0. After heatingfor a total of one hour at 520 F., external heating was dis-' continuedand the temperature of the reaction mixture was allowed to fall to 400F. 105 g. of glycerine was then added, and heating was resumed at 500 F.for about 107 minutes. The product thus obtained had' an acid value of10, color 8-9 (Gardner), and viscosity J-K (Gardner-Holdt) Example 4 Amixture consisting. of 300 g. soybean oil and 14.4 g. of maleicanhydride was heated for one hour at a temperature of 520 F. At the endof that time the acid value of the reaction mixture was 21.1. Thereaction mixture was allowed} to cool to 400 F. and 10.5 g. of glycerinewas then added. After heating the resulting mixture for one hour at 500F., there was obtained a product which had an acid value of 10.2, acolor of 8-9 (Gardner) and viscosity F (Gardner-Holdt).

Example 5 7 Example 6 Three-hundred g; of refined cotton seed oil washeated with '15 g. of furnaric acid in a carbon dioxide atmos" phere andwith mechanicalstirringto a temperature of 500 F. within 30 minutes andthen maintainedat that temperature for 115* hours. A sample taken fromthe reaction mixture at this point had an acid value of 29.0. Externalheating was then discontinued and to 109 g. of the reaction mixture thusobtained (a cotton seed oil-fumaric acid adduct), there was added 3.2 g.of pentaerythritol. The whole was then brought to a temperature of 525F. within 15 minutes and kept at this temperature for 1.5 hours. Theesterified adduct thus obtained had a color of 6 (Gardner) and aviscosity of I (Gardner-Holdt).

For purposes of comparison, to 105 g. of the above fumaric acid-cottonseed oil adduct there was added 3.1 g. of glycerine at a temperature of400 F., the mixture was heated to 525 F. within 15 minutes and thenmaintained at that temperature for 1.5 hours. There was thus obtainedthe glycerine ester of cotton seed oil-furnaric acid adduct having acolor of 6-7 (Gardner) and viscosity G (Gardner-Holdt).

Example 7 To 300 g. of linseed oil, heated to 300 F., there was added 15g. of fumaric acid. The resulting mixture was brought to a temperatureof 500 F. during 15 minutes and held at about this temperature foranother 1.5 hours. The linseed oil-fumaric acid adduct thus obtained hada color of 6 on the Gardner scale and viscosity F (Gardner- Holdt).

105 g. of the above adduct was heated to 480 F. and there was then addedto it 3.2 g. of pentaerythritol. The mixture was brought to atemperature of 520 F. and held at 520 530 F. for 1.5 hours.The'penta'er-ythritol ester of linseed oil-fumaric acid adduct thusobtained had a color of 7 on the Gardner scale and viscosity X('G'aIdner-Holdt) For purposes of comparison, 105 g. of the abovelinseed oil-f umaric acid adduct was brought to a temperature of 350 F.and there was then added to it 3.09 g. of glycerine. The mixture wasbrought to a temperature of 530 F. within 30' minutes and maintained atthis temperature for another 1.5 hours. The glycerine ester of linseedoil-fumaric acid adduct had a color of 7 on the Gardner scale andviscosity of U (Gardner- Hol'dt). t

' Example 8 Three-hundred g. of safilower oil was heated to 360 F.andthere was added to the heated oil 15 g. of furnaric acid, in acarbon: dioxide atmosphere and with mechani cal stirring. Thetemperature of the reaction mixture gradually was brought to 500 F. andthen held at'this temperature for about 1.5 hours. The safflower oil--fumaric acid adduct thus obtained had a color of 6 on the Gardner scaleand viscosity of E .(Gardner-Holdt).

To 105 g. of the adduct thus obtained therewas added, at atemperature of400 F., 3.2 g. of pentaerythritol,

and the resulting mixture was gradually brought to 525 V viscosity K(:Gardner-Hold't).

Example 9 Drying Time, Hours Film Tested Set to touch Tack-treePentaerythritol ester of soybean oil-fumaric acid adduct (Example 1)Pentaerythritol ester of soybean oil-maleic anhydride adduct (Example 2)Glycerine ester of soybean oil-fumaric acid adduct (Example 3) Glycerineester of soybean oil-maleic anhydride adduct (Example 4) Glycerine esterof soybean oil-maleic acid adduct (Example 5) Linseed oil-fumaric acidadduct (Example 7 Penteerythrltol ester of linseed oil-fumaric acidadduct (Example 7) Glycerine ester of linseed oil-fumaric acid adduct(Example 7) 2 Safllower oil-fumaric acid adduct (Example 6Pentaerythritol ester of safiiower oil-fumaric acid adduct (Example 8) 2Glycerine ester of safliower oil-fumaric acid adduct (Example 8) 3 notin 8 hours.

not in 24 hours.

not in 21 hours.

not in 24 hours. Cotton seed oil-fumaric acid adduct (Example 6)Pentaerythritol ester of cotton seed oil- Iurnaric acid adduct (Example6) Glycerine ester of cotton seed oil-fumaric acid adduct (Example 6)not in 48 hours.

not in 48 hours.

As herein stated, the quantity of fumaric acid employed in thepreparation of the present drying oils may be varied. While the aboveexamples all show the use of about 5 per cent by weight of the acidcomponent in order to present comparable data, fumaric acid in amountsas low as 3 per cent may be employed to obtain an oil of improved dryingproperties. The use of per cent or more of the fumaric acid is notdesirable. While the optimum quantity of fumaric acid employed is afunction of processing time and temperature, we have found that from,say, 3 per cent to 9 per cent of fumaric acid generally results inimprovement of the fatty oil. Oils of best drying properties, color andviscosity are obtained when employing an even more narrow range ofconcentration, say, from 4 per cent to 7 per cent of fumaric acid basedon the :weight of the fatty oil.

The processing of the oils is advantageously efiected in an inertatmosphere, e. g., in an atmosphere of nitrogen or carbon dioxide.However, formation of the present esterified adducts may also beeffected in air. While varying temperatures may be used, We have foundthat very little addition reaction takes place when the mixture of fattyoil and fumaric acid is processed at a temperature of below 200 C. (329F.). Optimum conversion is obtained at temperatures of from, say, 230 C.to 280 C. (446 F. to 536 F.).

As many apparently widely different embodiments of this invention may bemade without departing from the spirit and scope thereof, it is to beunderstood that the invention is not limited to the specific embodimentsthereof except as defined in the appended claims.

This is a continuation-in-part of our application, Serial No. 181,946,filed August 28, 1950.

What we claim is:

1. A drying oil comprising the pentaerythritol ester of an adduct offumaric acid and a non-conjugated, unsaturated, non-hydroxylated fattyoil having from 10 to 24 carbon atoms in the carbon chains of the fattyacids of the oil, said adduct being obtainable by heating the fatty oilwith from 3 per cent to less than 10 per cent by weight of fumaric acid.

2. A drying oil comprising the pentaerythritol ester of an adduct ofsoybean oil and fumaric acid, said adduct being obtainable by heatingthe fatty oil with from 3 per cent to less than 10 per cent by weight offumaric acid.

3. A drying oil comprising the pentaerythritol ester of an adduct oflinseed oil and fumaric acid, said adduct being obtainable by heatingthe fatty oil with from 3 per cent to less than 10 per cent by weight offumaric acid.

4. A drying oil comprising the pentaerythritol ester of an adduct ofcotton seed oil and fumaric acid, said adduct being obtainable byheating the fatty oil with from 3 per cent to less than 10 per cent byweight of fumaric acid.

5. A drying oil comprising the pentaerythritol ester of an adduct ofsafilower oil and fumaric acid, said adduct being obtainable by heatingthe fatty oil with from 3 per cent to less than 10 per cent by weight offumaric acid.

6. The method of improving the drying ability of a non-conjugated,unsaturated, n'on-hydr-oxylated fatty oil having from 10 to 24 carbonatoms in the carbon chains of the fatty acids of the oil which comprisesheating said oil with from 3 per cent to less than 10 per cent offumaric acid, based on the weight of said oil until formation of anadduct of the oil and fumaric acid, and then esterifying said adductwith pentaerythritol.

7. The method of improving the drying rate of soybean oil whichcomprises heating said oil with from 3 per cent to less than 10 per centof fumaric acid based on the weight of said oil until formation of anadduct of the oil and fumaric acid, and then esterifying said adductwith peutaerythritol.

8. The method of improving the drying rate of linseed oil whichcomprises heating said oil with from 3 per cent to less than 10 per centof fumaric .acid based on the weight of said oil until formation of anadduct of the oil and fumaric acid, and then esterifying said adductwith pentaerythritol.

9. The method of improving the drying rate of cotton seed oil whichcomprises heating said oil with from 3 per cent to less than 10 per centof fumaric acid based on the weight of said oil until formation of anadduct of the oil and fumaric acid, and then esterifying said adductwith pentaerythritol.

10. The method of improving the drying rate of safflower oil whichcomprises heating said oil with from 3 per cent to less than 10 per centof fumaric acid based on the weight of said oil until formation of anadduct of the oil and fumaric acid, and then esterifying said adductwith pentaerythritol.

References Cited in the file of this patent UNITED STATES PATENTS2,275,843 Clocker Mar. 10, 1942 2,306,281 Rust Dec. 22, 1942 2,363,016Oertling Nov. 21, 1944 2,678,934 Grummitt May 18, 1954

1. A DRYING OIL COMPRISING THE PENTAERYTHRITOL ESTER OF AN ADDUCT OFFUMARIC ACID AND A NON-CONJUGATED, UNSATURATED, NON-HYDROXYLATED FATTYOIL HAVING FROM 10 TO 24 CARBON ATOMS IN THE CARBON CHAINS OF THE FATTYACIDS OF THE OIL, SAID ADDUCT BEING OBTAINABLE BY HEATING THE FATTY OILWITH FROM 3 PER CENT TO LESS THAN 10 PER CENT BY WEIGHT OF FUMARIC ACID.